1. Field
Embodiments described herein relate generally to a motor driving circuit and a motor driving system.
2. Background Art
A conventional motor driving system includes a motor driving circuit, a motor, and a rotating load.
The motor driving system controls the number of revolutions of the motor with a number-of-revolutions controlling signal input to the motor driving circuit. Although the number-of-revolutions controlling signal may be a signal indicative of the pulse duty, the pulse frequency or the analog voltage, the following description will be focused on a case where the number-of-revolutions controlling signal is a signal indicative of the analog voltage.
The motor driving circuit measures the voltage of a circuit command signal, calculates the on-duty of the PWM output based on the measurement, and outputs a motor driving waveform. The motor driving circuit linearly increases the duty in proportion to the measured voltage.